SUBARU LEGACY 1997 Service Repair Manual

e. Malfunction indicator light

1Is always on.2Sometimes comes on.3Comes on only once.4Does not come on.
When does it come on?
Ignition key
position
1Lock2Acc3On (before starting engine)4Start5On after starting (Engine: run)
6On after starting (Engine: stop)
Timing
1Immediately after ignition is on.2Immediately after ignition starts.
3When advancing (Speedmiles/h,miles/h)4While traveling at a constant speed (Speedmiles/h)
5When decelerating (Speedmiles/h,miles/h)
6When turning (To right, to left, steering angledeg., steering timesec)
7When other electrical parts move (Part name:, Operating condition)
8When moving other electrical parts (Part name:, Operating condition)
2. SYMPTOMS
ABS operating
condition1Performs no work.2Operates only when abruptly applying brakes. (Conditions: vehicle speedmiles/h, how to step
on brake pedal)
3Operating time (sec., etc.)4Operating noise (Produced/Not produced)
5What kind of noise? (Knock, gong gong, bong, buzz, gong gong buzz, etc.)
6Reaction force of brake pedal (Stick, pressed down once with a clunk, pressed and released, etc.)
TCS operating
condition
1Performs no work.2Operates only when abruptly accelerating. (Conditions: vehicle speedmiles/h, how to step on
accelerator pedal)
3Operating time (sec., etc.)4Operating noise (Produced/Not produced)
5What kind of noise? (Knock, gong gong, bong, buzz, gong gong buzz, etc.)
6Whether or not operation indicator light comes on. (Come on/Does not come on, Others)
Behavior of
vehicle
1Directional stability cannot be obtained or steering arm refuses to work when applying brakes (vehicle turns to right, turns
to left, spins, etc.).
2Directional stability cannot be obtained or steering arm refuses to work when accelerating (vehicle turns to right, turns to
left, spins, etc.).
3Brakes are out of order (braking distance is long, brakes lock or drag, pedal stroke is long, pedal sticks, etc.).
4Poor acceleration (fails to accelerate, engine stalls, etc.).
5Vibration, abnormal noise (operating noise is loud, noise is produced during operation from the front of vehicle (right, left)
(tones:), noise is produced during operation from the rear of vehicle (tones:, others)
6Other phenomena (concrete symptoms)
3. CONDITIONS UNDER WHICH TROUBLE OCCURS
Environment1Weather (fine, cloudy, rain, snow, etc.)
2Ambient temperature (°C/°F)
3Road (urban area, suburbs, highway, general road, ascending slope, descending slope, paved road, gravel road, muddy
road, sandy place, etc.)
4Road surface (dry, wet, new-fallen snow, compressed snow, frozen slope, etc.)
Conditions
1Brakes (decelerationg, continuous/intermittent)2Accelerator (accelerationg, continuous/intermittent)
3Travel speed (miles, advancing, accelerating, reducing speed, low speed, turning, etc.)
4Condition of tire of each wheel (air pressure, degree of wear, whether or not genuine parts are used, whether
or not chain is passed around tires, whether or not T tire is used.) others ()
5Condition of suspension alignment ()
6Loading state ()
4. REPAIRED PARTS ARE USED OR NOT
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6. Diagnostics Chart for On-board Diagnosis System

C: INSPECTION MODE
The on-board diagnosis system is designed to detect prob-
lems while the vehicle is being driven. If a problem is found,
the ABS and TCS warning light will illuminate to inform the
driver of the occurrence of a problem. When the warning
light is on, the ABS/TCS system will be inactive and the
normal braking function will work. It is possible for the most
recent trouble code and history of problem to be stored in
memory until cleared.
B4M0082C
D: TROUBLE CODES
When on-board diagnosis of the ABS/TCS control module
detects a problem, the information will be stored in the EEP
ROM as a trouble code. (Stored codes will stay in memory
until they are cleared.)
1. CALLING UP A TROUBLE CODE
1) Take out diagnosis connector from side of driver’s seat
heater unit.
2) Turn ignition switch OFF.
3) Connect diagnosis connector terminal No. 4 to diagno-
sis terminal.
4) Turn ignition switch ON.
5) TCS warning light is set in the diagnostic mode and
blinks to identify trouble code.
6) After the start code (11) is shown, the trouble codes will
be shown in order of the last information first.
NOTE:
When there are no trouble codes in memory, only the start
code (11) is shown.
B4M0383A
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6. Diagnostics Chart for On-board Diagnosis System

B4M0082C
2. CLEARING MEMORY
1) After calling up a trouble code, disconnect ABS check
connector terminal No. 4 from diagnosis terminal.
2) Repeat 3 times within approx. 12 seconds; connecting
and disconnecting terminal No. 4 and diagnosis terminal
for at least 0.15 seconds each time.
3) Turn off the ignition key.
B4M0384A
NOTE:
After diagnostics is completed, make sure to clear memory.
Make sure only start code (11) is shown after memory is
cleared.
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6. Diagnostics Chart for On-board Diagnosis System

7. Diagnostics Chart for Warning Light
Circuit Failure
A: TROUBLE CODE DOES NOT APPEAR.
—TCS WARNING LIGHT COMES ON WHEN
STARTING THE ENGINE.—
1. Check TCS warning light.
OK
Not OK
Repair harness.
2. Check diagnosis terminal.
OK
Not OK
Repair harness.
3. Check diagnosis connector.
OK
Not OK
Repair harness/connector.
Replace ABS/TCS control module.
B4M0385



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7. Diagnostics Chart for Warning Light Circuit Failure

B4M0715A
1. CHECK TCS WARNING LIGHT.
1) Turn ignition switch OFF.
2) Disconnect all connectors from ABS/TCS control mod-
ule.
3) Turn ignition switch ON.
4) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P6) No. 3 — body / 10 — 14 V
B4M0387A
2. CHECK DIAGNOSIS TERMINAL.
1) Turn ignition switch OFF.
2) Measure resistance between diagnosis terminal and
body.
Connector/Specified resistance:
B81 — body / 0Ω
B4M0388A
3. CHECK DIAGNOSIS CONNECTOR.
1) Turn ignition switch OFF.
2) Disconnect all connectors from ABS/TCS control mod-
ule.
3) Measure resistance between diagnosis connector and
body.
Connector & terminal / Specified resistance:
(B82) No. 4 — body / 0Ω
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7. Diagnostics Chart for Warning Light Circuit Failure

B: ABS AND TCS WARNING LIGHT DO NOT
GO OFF.
—TCS OFF AND TCS OPERATING
INDICATOR LIGHTS COME ON AND GO OFF
PROPERLY WHEN STARTING THE ENGINE,
WHILE ABS WARNING AND TCS WARNING
LIGHTS KEEP ON.—
1. Check brake fluid level.
OK
Not OK
Add to brake fluid.
2. Check brake fluid level sensor.
OK
Not OK
Replace master cylinder.
3. Check harness connector between ABS/TCS
control module and alternator.
OK
Not OK
Replace harness connector.
Replace ABS/TCS control module.
B4M0389



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7. Diagnostics Chart for Warning Light Circuit Failure

1. CHECK BRAKE FLUID LEVEL.
Check that brake fluid level is above the MIN indication on
the reservoir tank.
B4M0716A
2. CHECK BRAKE FLUID LEVEL SENSOR.
1) Turn ignition switch OFF.
2) Disconnect connector from brake fluid level sensor.
Connector & terminal / Specified resistance:
(B16) No. 1—No.2/0Ω(Leaving float where it
is.)
(B16) No. 1—No.2/1MΩ(When pushing float
down.)
B4M0717A
3. CHECK HARNESS CONNECTOR BETWEEN ABS/
TCS CONTROL MODULE AND ALTERNATOR.
1) Turn ignition switch OFF.
2) Connect connector from brake fluid level sensor.
3) Disconnect all connectors from ABS/TCS control mod-
ule.
4) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P7) No. 20—body/2Vorless
5) Start the engine.
6) Measure voltage between ABS/TCS control module
connector and body.
Connector & terminal / Specified voltage:
(P7) No. 20—body / 10—14 V
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7. Diagnostics Chart for Warning Light Circuit Failure

C: TCS WARNING LIGHT AND TCS
INDICATOR OFF AND TCS OPERATING
INDICATOR LIGHTS COME ON AND GO OFF
PROPERLY, WHILE ABS WARNING LIGHT
DOES NOT GO OFF.
—TCS WARNING LIGHT AND TCS OFF
INDICATOR AND TCS OPERATING
INDICATOR LIGHTS COME ON AND GO OFF
PROPERLY WHEN STARTING THE ENGINE,
WHILE ABS WARNING LIGHT DOES NOT GO
OFF.—
1. Check harness connector between ABS/TCS
control module and ABS warning light.Repair harness connector.
Replace ABS/TCS control module.
B4M0392

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7. Diagnostics Chart for Warning Light Circuit Failure

B4M0393A
1. CHECK HARNESS CONNECTOR BETWEEN ABS/
TCS CONTROL MODULE AND ABS WARNING LIGHT.
1) Turn ignition switch OFF.
2) Disconnect connector from ABS/TCS control module
and TCS valve relay.
3) Measure resistance between ABS/TCS control module
connector and body.
Connector & terminal / Specified resistance:
(P6) No. 2—body/1MΩor more
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7. Diagnostics Chart for Warning Light Circuit Failure

D: ABS WARNING LIGHT ONLY REMAINS
ILLUMINATED.
—WHEN STARTING THE ENGINE, NEITHER
TCS WARNING, TCS OFF INDICATOR NOR
TCS OPERATING INDICATOR LIGHT COMES
ON EVEN ONCE, AND ABS WARNING LIGHT
AND MALFUNCTION INDICATOR LAMP
ILLUMINATE.—
1. Check input voltage of ABS/TCS control mod-
ule.
OK
Not OK
Repair harness/connector.
Replace ABS/TCS control module.
B4M0394

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7. Diagnostics Chart for Warning Light Circuit Failure